Warehouse operations generally have several door openings from which truck or rail cargos may be easily loaded and unloaded. These door openings are generally covered when not in use by doors that are specifically designed to be used as loading dock doors. The typical loading dock door has aspects of its design that make it suitable for loading dock operations, such as some ability to be locked and to provide security for the premises, a window through which to see if a truck or train is backed into the loading dock area, a wheel and track system that allows the door to be opened, either by lifting or rolling up in a vertical fashion, so that when opened it is out of the way of any traffic that results from the loading process.
Loading dock doors often sustain damage as large and heavy loads are moved at frequent high speeds by forklift operators through and around the openings on loading docks. A door that has been struck may be damaged and may, in some cases, not be easily or smoothly opened until it has been repaired and/or adjusted to work properly.
To address these issues, most loading dock doors have been designed to withstand a significant amount of abuse. Doors can be built to withstand greater amounts of abuse by using heavier gauge metals and/or braces for reinforcement to withstand greater strikes from forklifts. As these doors are built to be stronger, they also become heavier and more costly.
In some cases, the doors are designed to be able to release themselves from their tracks via a pivot system that has been built into the wheel and axle assemblies. Door systems that are designed to break away from their tracks have involved the creation of designed pivot points on the wheel assemblies or wheel axles. These break-away points allow the door to break away from the tracks and to be remounted with relative ease and a minimum amount of door damage. Unfortunately, the wheel assemblies are complicated, expensive and prone to breakage with continued use.